Pollution Prevention on Construction Sites: Washout, Fueling, Materials and Waste

Prohibited discharges

The EPA CGP prohibits these discharges from construction sites:

• Wastewater from concrete washout, unless managed by an appropriate control.
• Wastewater from washout and cleanout of stucco, paint, form release oils, curing compounds and other construction materials.
• Fuels, oils or other pollutants used in vehicle and equipment operation and maintenance.
• Soaps, solvents or detergents used in vehicle and equipment washing or external building washdown.
• Toxic or hazardous substances from a spill or other release.

Concrete washout

Concrete wash water is highly alkaline and carries fine cement particles. Under the CGP, for washout of applicators and containers of concrete, paint, stucco and similar materials:

• Direct wash water into a leak-proof container or a leak-proof, lined pit designed so it can't overflow from inadequate sizing or rain.
• Don't dump liquid wastes into drainage features, storm inlets or receiving waters, and don't dispose of them on the ground or by infiltration. Follow state and local disposal rules.
• Remove and dispose of hardened concrete with other construction waste.
• Locate washout activities as far away as possible from receiving waters, drainage features and storm drain inlets, in designated areas.

Fueling and equipment maintenance

• Fuel and maintain equipment in designated areas away from drainage features and inlets, on level ground.
• Use drip pans and absorbents; clean up leaks and spills immediately.
• Keep spill kits at fueling areas and in service trucks.
• Inspect equipment for leaks and repair them.
• Store fuel containers with secondary containment. Containers larger than certain thresholds may also trigger EPA's Spill Prevention, Control and Countermeasure (SPCC) rule.

Material storage

Minimize exposure of building materials, chemicals and products to rain:

• Store chemicals, paints, solvents and fertilizers under cover or in sheds, with secondary containment for liquids.
• Keep containers closed and labeled.
• Store materials away from drainage paths and inlets.

Waste and debris

• Provide covered dumpsters or waste containers with lids, and don't let them overflow.
• Keep construction and demolition debris, packaging and trash contained, especially on windy days.
• Locate portable toilets away from inlets and drainage features, on level ground, secured against tipping, and serviced regularly.

Spills and leaks

Under the CGP, operators must have procedures to prevent and respond to spills and leaks: train staff, keep spill kits accessible, clean up immediately, and report releases of hazardous substances or oil in reportable quantities to the National Response Center and other authorities as required.

Fertilizers

Under the CGP, apply fertilizers at rates consistent with the manufacturer's specifications, at the right time of year for vegetation uptake, and never before heavy rains, on frozen ground, or onto drainage features. Follow all other federal, state, tribal and local requirements.

Key takeaways

• Concrete, stucco, paint and similar washout water, fuels, oils, soaps and spills are prohibited discharges unless properly managed.
• Use leak-proof, lined, adequately sized washouts located away from drains and waters.
• Fuel and maintain equipment in designated areas with drip pans and spill kits.
• Cover materials and waste, and keep portable toilets away from inlets.
• Clean up spills immediately and report as required.

Last reviewed: October 25, 2026 · Free general education based on the Clean Water Act, EPA NPDES rules and the EPA Construction General Permit. Your governing permit (EPA, state, tribal or local) controls. This is not legal advice, not EPA-approved, and not a California QSP/QSD or other state credential, and it does not issue a certificate. Nothing you enter on this page is saved or sent.